The original message was received at Mon, 18 Feb 2008 07:44:30 -0800
from lb.z57.com [209.75.14.120]
----- The following addresses had permanent fatal errors -----
<h@b.com>
(reason: 550 Host unknown)
----- Transcript of session follows -----
550 5.1.2 <h@b.com>... Host unknown (Name server: b.com: host not found)